Over the past few weeks we’ve been getting multiple tips from developers saying that their apps are being tested with iOS 5. The new OS is being tested on all manner of iOS devices including iPods, iPads and iPhones. Unfortunately, we haven’t seen any unreleased devices likely because Apple is aware that usage logs go out to developers and wants to keep those devices under wraps.

This is interesting because widespread testing of apps usually precedes the developer release of a major iOS release by a few months.

Also interesting is that we’ve seen iPhone 3GS’s getting tested (not in the screenshot above, obv). It isn’t immediately clear if the final version of iOS 5 will support iPhone 3GS, but we do know Apple is testing it.

In the past, Apple has seeded new major iOS releases to developers in April, but obviously this year that’s not the case. We’re hearing that iOS 5 will be released in beta form to developers at WWDC in June, perhaps alongside a finished version of Mac OS 10.7, Lion.